He served as District Attorney for Elko County, Nevada from 1950 to 1958. Sawyer served as the Governor of Nevada from 1959 to 1967. He was defeated in his attempt at a third term by Paul Laxalt.

Governor Sawyer worked to push through civil rights policies and legislation, a difficult process in a state that had been accused of being "the Mississippi of the West."[6]

He was responsible for the development of the modern casino regulatory system with the passage of the Gaming Control Act of 1959 and the formation of the Nevada Gaming Commission. Sawyer swam against the tide of history when he unsuccessfully fought to prevent corporate ownership over Nevada casinos.

Sawyer was the first western governor to endorse the fledgling presidential campaign of Massachusetts Senator John F. Kennedy in 1960.

Commentators have reflected on Sawyer's career as follows: Grant Sawyer served two turbulent terms as Nevada's governor from 1959 to 1967. Sawyer was an advocate of progressive change. By the late fifties he had come so far from his start in the conservative political machine of Senator Patrick McCarran that many powerful Nevadans considered his policies on education, the environment, and civil rights to be dangerously radical. When he demanded meaningful regulatory control over casino gaming and took decisive action to purge the industry of its mob connections, the establishment's resistance stiffened. Eventually, Sawyer's positions brought him into open conflict with special interests and led to a collision with the justice department of the federal government, but he never backed down.

In the pilot episode of the television series Vegas, set in 1960, reference is made to the murder of "the governor's niece" named "Samantha Meade." Sawyer's name, however, is not specifically mentioned.